In all kinds of electronic, computer and mechanical devices, using a rotation connector to connect an element to a main body, such that the element may rotate along an axis in relation to the main body and that the element may interact with the main body, is a popular arrangement. For example, in a digital camera, a rotation lens may be connected to the main body of the camera with a rotation connector, such that the rotation lens may rotate along an axis in parallel to the front end of the main body of the camera and that photographs may be taken by aiming at the targeted object at different shooting angles.
For such a rotation connector a roller mechanism shall be provided. In addition to the roller mechanism, a stopper means must be provided to limit the rotation of the roller mechanism, such that the element connected by the rotation connector may rotate freely and may be fixed at particular angles, when certain functions need to be provided.
When the rotation connector is used in electronic elements such as rotation lens, free rotation of the roller mechanism is not allowed. A major reason is that all electronic components need to be connected to the man body with wire cable or flexible flat cable. When the roller rotates to a certain angle, the wire cable or the flexible flat cable will be damages due to the dragging force of the rotation lens. In addition to this, the electronic element that is connected by the rotation connector has an effective working angle. Designer of the device shall provide a braking mechanism to prevent the element from rotating to an angle that exceeds the effective working angle, such that the roller mechanism, the wire cable, the flexible flat cable or the electronic element won't be damaged due to improper operation of the user.
Moreover, for the rotation lens of a digital camera or other electronic elements that interact with external system, the rotation of the element may actuate a switch that changes the function mode of the element. For example, most digital camera operates in different function modes when the rotation lens faces front and rear, respectively. When the rotation lens faces a cover, the operation of the lens shall be switched off. Such a switching function has become necessary to similar devices.